The anhydrite is a rock-forming mineral, which mostly occurs in salt and evaporite deposits. It is closely associated with gypsum - anhydrite is actually gypsum without water. It is a calcium sulfate mineral that is commonly found in limestone and salt beds. Freshwater pearls are real, cultured pearls, grown in lakes, rivers, as well as ponds, which make them an affordable choice for jewelry-making because they are easier to extract.